The invention relates to methods of making dental prostheses from microwave curable dental compositions. The invention provides a method of making a dental prosthesis in which a pasty one component denture base resin polymerizable by microwave energy is injected into a mold enclosed by a flask. The flask has a body wall, at least a substantial portion of which is effectively transparent to the microwave energy. Useful in carrying out the method of the invention is a system which includes dental compositions containing Monomer(s) and an initiator system for initiation of polymerization of the Monomer(s) by application of microwave energy to form dental products having low shrinkage, high flexural strength and high modulus of elasticity. Dentures thus formed have a close fit to the patient""s mouth due to the low shrinkage of the pasty composition.
Prior art denture bases have been manufactured using powders based on polymethyl methacrylate and liquids based on methyl methacrylate, as see R. Janda, Ullmann""s Encyclopedia of Industrial Chemistry, Vol. A 8, Chap. 5.1 Denture Base Resins, p. 278/280, 1987 Editor VCH Verlagsgesellschaft Weinheim, Germany. These powder and liquid materials require mixing to form a dough. More than ten minutes after mixing the powder and liquid are required before the dough is moldable. The liquids contain more than 90% by weight methyl methacrylate which has a strong odor during processing, and the polymerized denture base material formed has an allergenic potential because of residual unpolymerized monomer.
Bean in U.S. Pat. No. 68,548 discloses improved apparatus for and method of casting aluminum. Housel in U.S. Pat. No. 283,487 discloses dentist""s flask. Joannides in U.S. Pat. No. 1,575,688 discloses manufacture of dental plates and apparatus therefore. Jackson in U.S. Pat. No. 2,341,991 discloses injecting mechanism for dental flasks. Hennicke et al in U.S. Pat. No. 2,660,758 discloses injection flask apparatus. Greene in U.S. Pat. No. 3,635,630 discloses denture molding apparatus including flask members with removable plastic inserts. Rohrer et al in U.S. Pat. No. 4,599,216 discloses apparatus for exposure to microwaves. Hampshire in U.S. Pat. No. 4,069,000 discloses mold for shaping and curing reinforced plastic material. Bekey et al in U.S. Pat. No. 4,182,507 discloses mold for casting articulated castings from registered dental impressions. Beu in U.S. Pat. No. 4,218,205 disclose three-section self-sealing dental flask. Kogure in U.S. Pat. No. 4,359,435 discloses method for manufacturing plastic products. Nakazato in U.S. Pat. No. 4,873,269 discloses resinous compositions for denture base. Uebayashi in U.S. Pat. No. 4,971,735 discloses fabricating method of resin base denture. Hasegawa et al in U.S. Pat. No. 5,063,255 discloses photopolymerizable type resin compositions for dental purposes. Oxman et al in U.S. Pat. No. 5,066,231 discloses dental impression process using polycaprolactone molding composition. McLaughlin in U.S. Pat. No. 5,094,619 discloses coloration of dental restorations. Masuhara et al in U.S. Pat. No. 5,104,591 discloses method for light curing of dental light-curing resins. Kuberasampath et al in U.S. Pat. No. 5,108,753 discloses osteogenic devices. Kimura in U.S. Pat. No. 5,151,279 discloses method for making resin dental plates and flasks. Lai in U.S. Pat. No. 5,158,717 discloses method of molding shaped polymeric articles. Fujii et al in Japanese Patent 62-54739 discloses vulcanization accelerator. Nakayama et al in Japanese Patent 60-214284 discloses pulse radar. Frisch in Offenlegungsschrift Patent DE 32 36 835 A1 discloses resin preparation for tooth prosthesis. Nakazato in Offenlegungsschrift DE 41 02 129 A1 discloses a method and device for products to repair from dental prosthesis synthetic material. Feurere et al in European Patent 0 089 705 B1 discloses procedure for the fabrication by molding. De Clerck in European Patent No. 0 193 514 B1 discloses procedure of polymerizing resins.
It is an object of the present invention to provide a method for making precisely fitting prosthesis, especially crowns, bridges, full or partial dentures using microwave energy to initiate polymerization.
It is an object of the present invention to provide a system containing a one component polymeric composition for producing dental prosthesis which is readily cured by using microwave energy and which has a polymerization shrinkage of less than 4% by volume.
It is an object of the present invention to provide a system containing a one component composition which is methyl methacrylate free.
It is an object of the present invention to provide a system containing a curable composition, including polymerizable acrylate and/or methacrylate Monomers having molecular weight between 120 and 50,000 and initiators adapted to remain stable and not initiate polymerization of the polymerizable Monomers when stored for more than one year at 23xc2x0 C.
It is an object of the present invention to provide a method of making a denture by injecting a one component composition into a mold within a closed flask.
It is an object of the present invention to provide a method of making a dental prosthesis by curing the injected one component denture base resin within a mold contained by a closed flask by applying microwave energy.
It is an object of the present invention to provide a method of making a dental prosthesis by providing a one component polymerizable composition and injecting the said composition into an enclosure having a body wall which is substantially transparent to microwave energy.
It is an object of the present invention to provide a curable system, including a microwave permeable flask enclosing a polymerizable composition having at least one polymerizable methacrylate or acrylate Monomer with a molecular weight between 120 and 50,000, preferably 120 to 20,000 g/mol, and fillers and a microwave energy sensitive initiator system adapted to permit the polymerizable compound to remain substantially and effectively free of polymerization, and moldable for at least one year when stored at 23xc2x0 C.
As used herein xe2x80x9cmicrowave transparentxe2x80x9d refers to materials through which microwaves are transmitted without being substantially absorbed.
As used herein xe2x80x9cdenturexe2x80x9d refers to a molded member formed with at least one artificial teeth embedded therein.
As used herein xe2x80x9cMonomersxe2x80x9d refers to monomers and/or oligomers.
Throughout this disclosure all percentages are percent by weight unless otherwise indicated.
The invention provides a curable system and method of making a dental prosthesis. The method of making a dental prosthesis includes providing a one component denture base resin composition which is polymerizable by microwave energy. The one component denture base resin composition is injected into a mold enclosed by a flask having a body wall which is substantially transparent to the microwave energy. The curable system includes microwave energy sensitive initiators and polymerizable (meth)acrylate Monomers having a molecular weight preferably between 120 and 20,000. The initiators are adapted to initiate polyermization of the polymerizable Monomers by application of microwave energy to the flask. The initiators are adapted to remain stable and not initiate polymerization of the Monomers for at least one year at 23xc2x0 C. in the absence of microwave energy.